Many charities make use of ‘matches’ on donations made by their supporters as a way of encouraging more and larger donations. The effectiveness of these matches in the field has been tested elsewhere, but it is unclear whether the current ‘standard’ matching formulation is the most effective. In two field experiments, we test different formulations of a matching programme against no match and a standard match. In both studies, which are administered digitally using email and social network sites, we find no statistically significant effects of any match (including the standard match) compared with the control condition. Taken together, these findings suggest that while matches can be effective, their effectiveness may depend on contextual factors and the type of donors being solicited.